Digital testing instrument



FIG. 1 is a top front elevational view;

FIG. 2 is a left side elevational view;

FIG. 3 is a right side elevational view;

FIG. 4 is a bottom back elevational view;

FIG. 5 is a top plan view; and,

FIG. 6 is a bottom plan view. 

The ornamental design for a digital testing instrument, as shown and described. 